A '''dermal bone'''
(membrane bone )- bony structures derived from [[intramembranous ossification]] that form components of the [[vertebrate]] skeleton including the skull, jaws, gills, fins and exoskeleton. In contrast to [[endochondral ossification|endochondral]] bone, dermal bone does not form from cartilage first and then calcify. Dermal bone is formed within the [[dermis]] and it grows by accretion only ; that is, the outer portion of the bone is deposited by [[osteocyte]]s.
The function of dermal bone is conserved throughout vertebrates,
varying in shape and numbers of bones in the [[skull roof]] and postcranial structures. In [[bony fish]], dermal bone is found throughout the body in the fin rays and scales. Special examples of dermal bones include the [[clavicle]], [[patella]], and ''os cordis''.